ITF Pharma update, page-3

*Cheryl Maley

FYI @sarge17

Australia; 14 October 2015: Starpharma (ASX: SPL, OTCQX: SPHRY) today announced the granting of a patent by the US Patent Office for VivaGel® related to the prevention of recurrence of bacterial vaginosis (BV). The patent’s term is to 2032 providing an extension of seven years over granted VivaGel® patents. Additional term (up to 5 years) may also be available subject to timing of regulatory approval. This US patent builds on the company’s VivaGel® patent portfolio that underpins the VivaGel® BV products. The VivaGel® patent portfolio comprises granted patents in key markets, including in Europe where the product recently received marketing approval for the topical treatment and rapid relief of BV, including symptomatic relief of vaginal odour and discharge. The current market for the management of BV and associated symptoms is estimated to be in excess of US$1 billion globally, with significant areas of unmet need for BV sufferers, especially women with recurrent BV. Bacterial vaginosis is the most common vaginal infection worldwide affecting millions of women annually. It is associated with an increased risk of pre-term births, miscarriage, and transmission and acquisition of STIs, including genital herpes and HIV/AIDS. Recurrence of BV has been estimated to occur in around 60% of women treated for BV, and there is currently no approved therapy available for prevention. As well as being an effective treatment for the relief of BV symptoms, ongoing use of VivaGel® BV was shown in a phase 2 clinical study to reduce recurrence of BV. A phase 3 clinical trial programme for VivaGel® BV for prevention of recurrent BV is progressing well in North America, Europe and Asia.

Patent term extensions in Australia and beyond: Part 1
Vanessa Yeung
March 28, 2023
Articles, blog, Patents
The concept of patent term extensions is one that is widely known amongst those in the pharmaceutical industry. It refers to an extension granted to a patent that covers a pharmaceutical product that has undergone regulatory approval. The purpose of a patent term extension (PTE) is to compensate for the delays that have occurred during the process of obtaining regulatory approval, so as to encourage pharmaceutical research and development.
We have prepared a brief reference guide, in four parts, to help explain the process in Australia and key jurisdictions, including the US and Europe.
Not all countries provide for patent term extension, for example New Zealand. However, those countries that do provide such provisions include Europe, the United States, Singapore, Japan, Taiwan, South Korea, Israel, Russia, Ukraine and several others. This article discusses patent term extensions in Australia, and how this differs relative to patent term extensions in major jurisdictions, including the United States and in Europe, so that patentees can better protect their pharmaceutical products across international markets.
The basics of regulatory approval for pharmaceutical drug products
For pharmaceutical products to be sold in Australia, it is essential that the product is included in the Australian Register of Therapeutic Goods (ARTG), which is regulated by the Therapeutic Goods Administration (TGA). The role of the TGA is to assess therapeutic goods to ensure that they are safe and effective prior to receiving approval for use in Australia. The process of regulatory approval often takes many years, during which time the patent term has already commenced. Aside from pharmaceutical products, the same process also applies to medical devices and in vitro diagnostic manufacturers.
In the United States, the Food and Drug Administration (FDA) is the equivalent of Australia’s ARTG, in that drug approval must be sought via the FDA prior to marketing the relevant product in the US.
In Europe, marketing authorisation is obtained either via the European Medicines Agency (EMA) or the UK’s Medicines and Healthcare products Regulatory Agency (MHRA). Since the UK left the European Union on 31 January 2020, and during the transition period up until 1 January 2021, UK marketing authorisations obtained by the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) were converted into Great Britain marketing authorisations. Post-Brexit, following expiry of this transition period, the process of obtaining marketing authorisations in the UK now differs slightly. Specifically, UK marketing authorisations obtained by MH7RA are valid across the whole of the UK, whereas Great Britain marketing authorisations obtained by the MHRA are valid only in Great Britain (England, Scotland and Wales), and for marketing authorisation in Northern Ireland these continue to be obtained via the EMA, despite Northern Ireland being part of the UK.
Thus, many of the products that are approved for marketing in the UK may be covered by both a Great Britain marketing authorisation, as well as a Northern Ireland EMA marketing authorisation. Post-Brexit, this also means that marketing authorisation granted by MHRA, does not count as “first authorisation” for placing the product on the European market.
How long is the patent term extension?
In Australia, the standard patent term is 20 years from the date of filing. Upon grant of an extension of term, pharmaceutical patents can further benefit from an extension of up to 5 years.
Calculating the actual length of an extension, involves working out the period between the date of the patent and the date of the earliest first regulatory approval, reduced by 5 years (section 77 of the Patents Act).
Essentially this means that where the period between the two dates is 5 years or less, an application cannot be made for an extension of term. Likewise, where the period between the two dates is 10 or more years, this would allow for the full 5-year extension of term to be applied. Any period between 5 and 10 years, will be calculated and an extension of term will be granted for between 0 to 5 years.
In the US and in Europe, the maximum patent term extension is also 5 years, and the calculations for determining the extension are similar. However, if the regulatory product is for paediatric use, the term can be further extended for an additional 6 months, which gives a total patent term extension of up to 5 years and 6 months for paediatric drug products.
Post-Brexit, the UK has retained this provision, so that UK patents covering a product that has received marketing authorisation for paediatric use, are eligible for a further 6 month extension. However, advantageously post-Brexit, the requirement to provide evidence of marketing authorisation in all European Economic Area (EEA) states (Iceland, Liechtenstein, Norway and Switzerland) has been removed, so that it may now be possible to receive grant of a 6 month extension of term, even though approval for paediatric use was not obtained in all these EEA states.
Given that Australian patent laws follow European patent laws quite closely, it is surprising that the provisions concerning patent term extensions do not currently extend to provide additional term protection for paediatric products, although this could change in the future.

Eligibility
i) Australia
In Australia, the eligibility criteria for which patent term extensions can be applied for, can be found under section 70 of the Patents Act, which states that:
The patent must disclose and claim a pharmaceutical substance per se, or a pharmaceutical substance when produced by recombinant DNA technology;
Any goods containing or consisting of that particular pharmaceutical substance must be included in the Australian Register of Therapeutic Goods (ARTG); and
The first regulatory approval for that pharmaceutical substance must have occurred more than 5 years after the filing date of the patent application.
A pharmaceutical substance may encompass a mixture or compound of substances for therapeutic use whose application involves:
a) A chemical interaction, or physico-chemical interaction, with a human physiological system; or
b) Action on an infectious agent, or on a toxin or other poison, in a human body.
In understanding what is meant by the terms “a pharmaceutical substance per se”, the case of Boehringer Ingelheim International v Commissioner of Patents [2000] FCA 1918 has been authoritative in Australia. In essence, the pharmaceutical product or substance itself must be new and inventive. Thus, a pharmaceutical substance that is produced by a particular method or process (product by process claims), or pharmaceutical substances used in a novel and inventive way for treatment, will not be eligible for an extension of term, unless that process by which the pharmaceutical substance is produced involves the use of recombinant DNA technology (See also Commissioner of Patents v AbbVie Biotechnology Ltd [2017] FCAFC 129 at para [55]).
However, in some circumstances whereby a novel and inventive pharmaceutical substance can only be defined when also considering the process by which it was made, which may be the case when the exact chemical composition or structure of the substance is not fully characterised, it may then be possible to obtain an extension of term, when using claims in the format of “a pharmaceutical substance of X obtainable by the process or methods of Y” (Zentaris AG [2002] APO 14, and also Pharmacia Italia SpA v Mayne Pharma Pty Ltd [2006] FCA).
Further examples of case law that have discussed the meaning of the terms “a pharmaceutical substance per se” include Spirit Pharmaceuticals Pty Ltd v Mundipharma Pty Ltd [2013] FCA 658. In this case, the patent claims were directed towards a controlled release oxycodone formulation, characterised by dosage amounts, excipients and/or release profile. It was ruled in this case that the pharmaceutical substance per se was the mixture of oxycodone and the relevant excipients that enabled the pharmaceutical substance to achieve the claimed result.
In comparison, the case of iCeutica Pty Ltd [2018] APO 76, involved a composition containing nanoparticulate diclofenac, which was listed on the ARTG. Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that is used to commonly treat pain and inflammation. While diclofenac was the substance responsible for the chemical interaction, it was found that instead its physical form constituted a pharmaceutical substance per se, as it was determined by the Commissioner that the particle size of diclofenac contributed to the solubility and activity of the diclofenac.
In Australia, claims for protecting a pharmaceutical substance per se, must be drafted in an appropriate form if the Applicant intends to apply for an extension of term. The case of Biogen International GmbH v Pharmacor Pty Ltd [2021] FCA 1591, exemplified that claims drafted in Swiss-style form, wherein “substance X for use in the treatment of disease Y”, are purpose limited product claims, and thus are not suitable for protection of a pharmaceutical substance per se.
ii. United States
In the US, patent term extensions are provided by the Hatch-Waxman Act 1984, under section 35 U.S.C § 156, and covers drug products for human use, medical devices and veterinary products. The eligibility criteria in the US, requires that at least one claim in the granted patent must cover the approved drug product, the approved product must not have been commercially sold prior to regulatory approval, the patent must also be in force, the application must have been made during the time that the patent is in force, and the patent should not have already received a previous extension of term.
In clarifying the meaning of the requirement that “at least one claim in the granted patent must cover the approved drug product”, this can include the product itself, a method of using the product or a method of manufacturing the product.
Interestingly, despite the FDA classifying combination drug-device products to be either a drug or a medical device, this would make no difference for the purposes of applying for a patent term extension, under 35 U.S.C. § 156 of the Act. This is because, if either the drug or the device is eligible for a patent term extension, this eligibility will extend to the drug-device combination, which is similar to the considerations given to products containing a combination of drugs.
With respect to patent term extensions on drug-device combinations, the case of Angiotech v Lee, 191 F.Supp.3d 509 (E.D. Va. 2016) has been of significant interest in the US. In this case, the patentee sought an extension of term on their patent for a drug-device combination, which included claims directed towards a method of biologically stenting a blood vessel to prevent narrowing of mammalian arteries. The request for an extension of term was ultimately denied on the grounds that the patent did not claim a method of using the stent to administer the drug. It was stated that in order for the patent to claim a method of using the device, the patent “must recited one or more structural elements of the device… to the exclusion of chemical features”. The claim in question, was considered to focus on biological rather than physical stenting, and therefore did not recite the structural elements of the stent, as required by the Act. Thus, the patent did not qualify for the extension, since there were no claims covering a method of using the stent device.
The types of claims in a patent for which an extension of term is sought in the US, is therefore different from those considered acceptable in Australia.
iii) Europe
In Europe, the equivalent to a patent term extension is a supplementary protection certificate (SPC), which is applicable to medicinal, veterinary or a plant protection product. The provisions that govern SPCs are outlined under Regulations (EC) No. 469/2009 for medicinal products and (EC) No. 1610/96 for plant protection products.
Unique to European practice, SPCs are currently national rights, and therefore must be applied for separately in each country for which protection is sought. SPCs are available in all European Union countries, as well as in some non-European Union countries, such as Switzerland, Norway, Iceland, Bosnia, Serbia and several others. With the European Unified Patent Court due to commence on 1 April 2023, it is likely that the European Commission may seek to introduce a new unitary SPC in the near future, especially since application of the Regulations often differs between different European countries, depending on the interpretations applied. For example, medical devices have been granted SPCs in Germany, whereas the same is not considered eligible for an SPC in the UK, France, Spain and Denmark.
When applying for an SPC in Europe, the product on which the patent is based must have valid marketing authorisation. In addition, there must be at least one claim in the granted patent covering the product, and the patent must be in force in the country for which the SPC is sought.
In Europe, the requirement of having “at least one claim in the granted patent covering the product” includes claims that not only cover the active ingredient(s) of the authorised commercial product, but also include claims directed towards use of that product, for example, in the treatment of a particular disease, or a method of manufacturing said product, and in the case of plant protection products, a preparation containing the active ingredient(s). Thus, the claim does not necessarily need to be restricted to the product per se, as is the case in Australia.
Post-Brexit, the processes associated with applying for an SPC in the UK remains largely the same, as though the UK was still a member state of the European Union. Applicants will still require a valid UK patent covering the regulatory approved product, the product claimed in the patent must be received the first authorisation in the UK, and the marketing authorisation must have been granted by either the European Medicines Agency (EMA) or the UK’s Medicines and Healthcare products Regulatory Agency (MHRA).

First regulatory approval
i. Australia
In Australia, where claims in a pharmaceutical patent application encompass several pharmaceutical substances, the meaning of the phrase “first inclusion in the ARTG” is reference to the earliest date on which at least one substance falls within the scope of the claims, was included in the ARTG (Pfizer Corp v Commissioner of Patents (No 2) [2006] FCA 1176 at para [34]). The phrase “first inclusion in the ARTG” was also discussed in the case of Abbvie Biotechnology Ltd [2015] APO 45, whereby it was emphasised that the earliest regulatory approval date, was the date that the goods were first registered, and not the date of subsequent inclusions for various different indications.
However, in further illustrating the concept of “first inclusion in the ARTG”, the Australian case of Ono Pharmaceutical Co, Ltd v Commissioner of Patents [2021] FCA 643, has been significant, in that it was discussed whether a third-party pharmaceutical product falling within the scope of the claims of a pharmaceutical patent, constituted “first inclusion” on the ARTG. In this case, Ono Pharmaceuticals sought an extension of term on their patent for the pharmaceutical product Opdivo. The Australian Patent Office rejected Ono Pharmaceuticals’ application for an extension of term, on the grounds that Keytruda, a third party’s product, fell within the scope of the claims, and for which received an earlier regulatory approval date 9 months prior. Thus, in the Patent Office’s opinion, Keytruda was the “first inclusion” on the ARTG of a pharmaceutical product falling within the scope of the patent claims. Ono Pharmaceuticals subsequently appealed this decision, which was overturned by the Federal Court of Australia as it was held that an application for a patent term extension should be based on the patentee’s own product, and not that of a third-party. Therefore, interpretation of the terms “first inclusion in the ARTG” is reference to the earliest registered product on the ARTG of the patentee, and not to goods registered to third parties.
This interpretation was considered the more sensible approach, since this would be consistent with the entire purpose of the patent term extension regime, whereby patentees are able to restore time lost on their patent term due to the need to gain marketing approval when developing and commercialising a new pharmaceutical substance. The alternative interpretation would have required extensive searches to be conducted on the ARTG to check the “first inclusion” on the ARTG and whether or not this was a product of the Applicant to the extension of term or to a third party, which would be onerous and a burden to determine. In the Federal Court’s words, “a liberal rather than a literal construction (of the term “first inclusion in the ARTG” is to be preferred”. Whilst the case did not discuss licensees or sponsors of an ARTG product, it is likely that such commercial arrangements will be considered favourably when assessing patent term extensions.
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ii. United States
In the US, the first regulatory approval is in fact reference to the first regulatory approval of the “active ingredient”. Specifically, the “active ingredient” of a product must not have previously been approved by the FDA, either alone or in combination, for the patent claiming such to be eligible for a patent term extension. In considering chemical compounds, in the case of Ortho-McNeil v. Lupin (Fed. Cir. 2010) the Federal Circuit held that the enantiomer Levofloxacin, was eligible for a patent term extension, as it was different from its racemic compound ofloxacin, which was previously approved by the FDA. In another case of Photocure v Kappos (Fed. Cir. 2010) it was held that a patent covering the active methyl ester form of a drug product was not eligible for a patent term extension on the grounds that a previously approved product utilized the same active moiety for the same therapeutic use.
Even if a patent covered the same active ingredient but for a different therapeutic use, this would also not be eligible for a patent term extension, on the basis that the pharmaceutical product would have already received approval for marketing or use of this active ingredient. To illustrate this further, the case of Fisons v Quigg, 876 F.2d 99 (Fed. Cir. 1989) three different forms of a drug product were covered by separate patents, which all contained the same active ingredient, cromolyn sodium. Three separate applications for a patent extension of term were made for each of the three patents. However, in all three cases, the application was refused on the grounds that cromolyn sodium received prior FDA approval for a different use back in 1973. It was held by the Federal Circuit that the term “product” in the Act should be interpreted as the “active ingredient of a new drug”.
In considering this interpretation further, the case of Glaxo Operations UK Ltd v Quigg, 894 F.2d 392, 394 (Fed. Cir. 1990) discussed that the “active ingredient of a new drug” includes “any salt or ester of the active ingredient”. Specifically, in this case FDA approval was obtained for cefuroxime axetil, an ester of cefuroxime, an organic acid. The test used by the Federal Circuit in deciding whether the patent covering cefuroxime axetil was eligible for a patent term extension, relied on assessing whether cefuroxime axetil, or a salt or ester of cefuroxime ester had previously received FDA approval. Upon review, it turned out that there was prior regulatory approval of salts of cefuroxime acid, but not for cefuroxime axetil, or a salt or ester of cefuroxime ester. Thus, the patent covering cefuroxime axetil was eligible for a patent term extension.
Patentee seeking patent term extensions in the US must therefore be cautious, especially if their patent portfolio includes multiple patents covering different aspects of a particular FDA-approved product, for example one patent covering methods of use of the product, and another patent covering the composition of the product, since only one patent containing the “active ingredient” can receive a patent term extension.
Noticeably, this contrasts with the position in Australia, in that one patent term extension can be granted per patent, and patent term extensions can be applied to multiple patents that rely on the ARTG registration of a single pharmaceutical substance.
iii. Europe
A similar scenario exists in Europe, in that a product protected by a patent for which a SPC is sought, must not have previously received marketing authorisation (Santen, C-673/18). Thus, any new use of a product that previously received marketing authorisation is not eligible for a SPC (Abraxis Bioscience, C-443/17; Santen, C-673/18).
Crucially, the decision in Santen overturned the earlier decision of Neurim Pharmaceuticals (C-130/11), which otherwise held that SPCs could be granted on patents that covered second medical use on a pharmaceutical product that had already received marketing authorisation for a different application. The reason why the decision in Neurim Pharmaceuticals was overturned was because in Santen, the scope of the meaning of “different (therapeutic) application” was discussed on whether this term encompassed different formulations, dosages and/or other methods of administering the product. It was held by the Court of Justice of the European Union (CJEU) that a narrow interpretation should be applied. Specifically, it was held that “the first marketing authorisation” for a product is reference to the “first marketing authorisation for a medicinal product incorporating the active ingredient or the combination of active ingredients at issue irrespective of the therapeutic application of that active ingredient, or of that combination of active ingredients, in respect of which that marketing authorisation was obtained”. Thus, it was considered that the interpretation applied in Neurim would be erroneous, since this would otherwise result in SPCs being granted for all types of research. Specifically, it was held that the purpose of the SPC Regulations was “to protect research leading to the first placing on the market of an active ingredient or a combination of active ingredients as a medicinal product” (paragraph 55 of Santen), interpretations to the contrary would therefore not protect the interests of the public.

Can an extension of term be sought for patents containing a combination of pharmaceutical products?
In Australia, the case of Merck Sharp & Dohme Corp v Sandoz Pty Ltd [2021] FCA 947, has been significant in discussing this question in some detail. The case itself was discussed in an earlier article, written by our Senior Associate, David Tso. To briefly summarize, the claims of the pharmaceutical patent issued to Merck were directed to a compound sitagliptin, and a composition containing a combination of sitagliptin and metformin. A patent term extension was granted to Merck on the combination of sitagliptin and metformin, since it received regulatory approval 5 years after grant of the patent, whereas sitagliptin on its own would have received regulatory approval less than 5 years after grant of the patent. However, when challenged by Sandoz, it was found that an error had occurred in calculating the extension of term, since the patent term extension was not based on sitagliptin alone. In other words, the patent term extension was not based on the pharmaceutical substance with the first regulatory approval date. The Federal Court ruled that if Merck was allowed to retain the current patent term of extension, they could obtain “a monopoly over sitagliptin for more than 20 years in circumstance where it never suffered an unacceptable delay in its capacity to exploit sitagliptin” (at para [87]). Thus, the Register of Patents was subsequently rectified, and the extension of term reduced to zero.
In light of this decision, where a patent claims a combination of pharmaceutical substances, it has become preferable in Australia to have separate patents for each pharmaceutical substance that has or will receive regulatory approval, so that each patent can receive an extension of term to which they are entitled to, based on their eligibility for such.
As discussed earlier, the US considers the first regulatory approval of the “active ingredient”. Where a US patent claims a combination product that contains one or more active ingredients, whereby one or more of these active ingredients previously received regulatory approval, at least one of the claimed active ingredients must be new in order to qualify for a patent term extension. This concept was discussed in the case of Arnold Partnership v. Dudas, 362 F.3d 1338, 1341 (Fed. Cir. 2004), whereby a pharmaceutical product encompassed the combination of hydrocodone and ibuprofen, both of which previously received separate FDA approval. The Court held that a patent term extension for a combination therapy is only available where the active ingredients, when considered separately, have not been previously marketed. In other words, if at least one of the claimed active ingredients was new, and had not received prior FDA approval, then the patent would have been eligible for a patent term extension, even if there is a new synergistic effect from using the combination of the previously approved active ingredients.
Considering a similar scenario in Europe, for patents claiming products that contain two or more active ingredients that together deliver a combined effect, there is case law in Europe that points towards the fact that for a valid SPC application, the patent claims do not necessarily need to explicitly mention the combination of active ingredients (Teva UK Ltd & Others v Gilead Sciences Inc. [2018] C-121/17). Instead, it should be possible for the skilled addressee to determine the combination of active ingredients of the product based on the prior art at the date of filing the patent in question. Thus, where a patent utilises broad claims wherein at least one active ingredient is unknown is sufficient to invalidate a SPC application.
Patent rights during the extension of term
If an extension of term has been granted, it is important to note that the rights of the patentee are limited, in the sense that it is not considered an infringement if there is exploitation of the pharmaceutical substance for any purpose other than a therapeutic use. Furthermore, it is not an infringement of the pharmaceutical patent if there is exploitation of the pharmaceutical substance in another form, meaning that only the pharmaceutical substance per se is protected.
This concept of limited extended protection is similar in the United States and in Europe.
Patent term extensions in the US only extend the exclusive patent rights to any regulatory approved use of the product. In other words, if the patent claims several products, in addition to the regulatory approved product, only the product that has received FDA approval will receive extended patent rights, whilst the exclusive rights of the remaining non-approved products in the patent will expire when the original patent term ends.
Likewise, in Europe, SPCs extended protection covers the same protection that was offered by the patent, in that if the patent claims covered only use of the product for a particular purpose, then the SPC will offer the same protection, covering only use of the product for that stated purpose.
Simone Van Der Koelen Htdq9z64vpo Unsplash
Photo by Simone van der Koelen on Unsplash
When to apply for a patent term extension
In Australia, the application for an extension of term must be made within 6 months of the date of grant of the patent, or the date from when the pharmaceutical substance was first included in the ARTG, whichever is later.
Along similar lines, the deadline for applying for a SPC is 6 months from the time the product received marketing authorisation for most European countries.
Crucially however, the deadline to apply for a patent term extension in the US is much shorter, with the deadline falling within 60 days of the product receiving approval from the FDA. This deadline is non extendable.
Extension of time to apply for an extension of term
As mentioned above, the deadline to apply for a patent term extension in the US is non-extendible. However, in Australia there are generous provisions under 223 of the Patents Act that allow for an extension of time to apply for an extension of term.
The relevant provisions in Australia states the patentee must be able to demonstrate that an error or omission has occurred, or there has been circumstances beyond their control that led to the error or omission for doing the relevant act.
There have been some cases that have discussed the concept of an extension of time to apply for an extension of term, in Australia. These include:
Alphapharm Pty Ltd v H Lundbeck A/S [2014] HCA 42, wherein it was discussed that where an extension of term is applied for during the term of the patent, section 223 of the Patents Act can be applied to extend the time in which to apply for said extension of term.
Secondly, in Boehringer Ingelheim International GmbH [1999] APO 60, it was discussed that where a patent has already been expired, an application for an extension of time cannot be filed. Thus, emphasizing the need to file for an extension of time during, and not outside of, the term of a patent.
In Europe, as mentioned above, SPCs are national rights. Thus, extension requests must be made before each national patent office, although the process for doing so in most European countries is similar. This is also true for paediatric SPCs, the application deadline for which is no later than two years prior to the expiration of the SPC.
Specifically, most European countries require that the SPC holder, when applying for a paediatric SPC extension, provides evidence that the deadline was missed despite “all due care” being undertaken, which carries a much higher proof burden, in comparison to that required in the UK. This typically requires a thorough explanation of how the patent records are maintained, how the record system generates reminders for upcoming deadlines, and in light of all those factors, explaining how in that particular instance, the deadline for applying for the SPC was overlooked.
In the UK, an extension of time can be sought to apply for the extension of term, if evidence is provided to demonstrate that it has always been the applicant’s intention to apply for the paediatric extension. In other words, the burden of proof is much lower, requiring only demonstration of intention, and that once the error was known, the applicant had acted diligently to resolve the error. This requirement is noticeably similar to section 223 of the Australian Patents Act.
Key takeaway points
For patentees of pharmaceutical products seeking to obtain patent term extensions in overseas jurisdictions, we advise that claims in a single patent application should be directed to a single pharmaceutical substance. Even though this would likely cost more than having a single patent application covering two separate pharmaceutical substances, separate applications allow applicants to take full advantage of any patent term extensions that may be granted, at least in Australia. We also advise that care should be taken with respect to use of Swiss style claims in Australia, since use of these claims could affect validity of a patent term extension. It is advisable for pharmaceutical patentees seeking a patent term extension on a global pharmaceutical patent portfolio to work towards the US deadline, not least because the deadline for applying is much shorter than in Australia and Europe, but also because the deadline is not extendible. This is particularly important to consider if the US is a market of interest.

Link below

https://www.mbip.com.au/patent-term-extensions-in-australia-and-beyond-part-1/